1. Field of the Invention
This invention relates to improvements in a side door hinge mechanism utilizing a quadric crank chain in a motor vehicle.
2. Description of Related Art
In most cases, the side door in a motor vehicle, such as a passenger car, is installed in a manner to be rotatable about a hinge affixed to a vehicle body for opening or closing. In order to allow an occupant of the motor vehicle to open or close the side door for getting in or out of the motor vehicle, a door opening angle corresponding to the total length of the side door is required. As a result, when free space adjacent side of the motor vehicle is small, it is oftentimes difficult for the occupant to get in or out of the vehicle because the side door cannot be opened sufficiently.
As noted in many publications such as U.S. Pat. Nos. 3,074,755 and 3,095,600, there have been proposed a side door hinge mechanism utilizing a quadric crank chain to overcome the above-mentioned difficulties.
Furthermore, as disclosed in U.S. patent appllication Ser. Nos. 611,149, 611,216 and 611,339, as shown in FIG. 1, a side door hinge mechanism in a motor vehicle having a quadric crank chain may include: a first rotary link 4 interconnecting a vehicle body 2 and a side door 3 and supported by rotary shafts 2A and 3A disposed on the vehicle body 2 and the side door 3, respectively; a second rotary link 5 interconnecting the vehicle body and the side door 3 and supported by rotary shafts 2B and 3B; a portion between the two rotary shafts 2A and 2B on the vehicle body 2; and another portion between the two rotary shafts 3A and 3B on the side door 3.
In the drawing, designated at 6 is a front pillar, 7 a front wheel and 8 a movable fender capable of rocking with the rotary link 4.
In the side door hinge mechanism utilizing the above-described quadric crank chain, the required space for the side door can be reduced while a desired space around feet of the occupant is maintained. As a result, even when the space at the side of the door is small, the occupant can open or close the side door 3 to get in or out of the vehicle.
However, when the first rotary link 4 and the second rotary link 5 are arranged as shown in FIG. 1, the rear rotary shaft 3B of the second rotary link 5, i.e. the rear link, is disposed at the substantially central portion in the longitudinal direction of the side door 3, and consequently, most of the second rotary link 5 is exposed to the compartment.
Consequently, such disadvantages are presented that the getting in or out of the vehicle by the occupant may be constricted by the second rotary link 5, which also detracts from the appearance of the interior of the compartment.